<template>
  <div class="transfer">
    <div class="transfer-panel">
      <p class="transfer-panel-header">
        <span>{{titleTexts && titleTexts[0]}}</span>
        <span>{{leftSelection.length}}/{{leftTableData.length}}</span>
      </p>
      <div v-if="showQuery">
        <el-form :inline="true" :model="leftQueryCondition" class="query-form">
          <slot name="leftCondition" v-bind:scope="leftQueryCondition"></slot>
          <el-form-item>
            <el-button type="primary" @click="onLeftQuerySubmit()">{{queryTexts[0]}}</el-button>
          </el-form-item>
        </el-form>
      </div>
      <el-table
        ref="leftTable"
        size="small"
        :max-height="maxHeight"
        :height="minHeight"
        :data="leftTableData"
        :row-key="tableRowKey"
        :row-style="handleRowStyle"
        @row-click="handleLeftRowClick"
        @selection-change="handleLeftSelectionChange"
        border
        stripe>
        <el-table-column
          width="40px"
          type="selection"
          :selectable="handleSelectable"></el-table-column>
        <el-table-column
          v-for="col in leftColumns"
          :prop="col.id"
          :key="col.id"
          :label="col.label"
          :width="col.width">
          <template slot-scope="scope">
            <slot v-bind:scope="{row: scope.row, col: col}">
              <span>{{scope.row[col.id]}}</span>
            </slot>
          </template>
        </el-table-column>
      </el-table>
      <el-pagination
        v-if="showPagination"
        @size-change="handleSizeChange"
        @current-change="handleCurrentChange"
        :current-page="pageIndex"
        :page-sizes="[10, 20, 50, 100]"
        :page-size="pageSize"
        :pager-count="5"
        :total="totalSize"
        layout="total, sizes, prev, pager, next">
      </el-pagination>
    </div>
    <div class="transfer-buttons">
      <el-button
        type="primary"
        :class="buttonClasses"
        :disabled="disabledLeftButton"
        @click.native="addToRight">
        <span v-if="buttonTexts[0] !== undefined" class="button-text">{{ buttonTexts[0] }}</span>
        <i class="el-icon-arrow-right"></i>
      </el-button>
      <el-button
        type="primary"
        :class="buttonClasses"
        :disabled="rightSelection.length === 0"
        @click.native="addToLeft">
        <i class="el-icon-arrow-left"></i>
        <span v-if="buttonTexts[1] !== undefined" class="button-text">{{ buttonTexts[1] }}</span>
      </el-button>
    </div>
    <div class="transfer-panel">
      <p class="transfer-panel-header">
        <span>{{titleTexts && titleTexts[1]}}</span>
        <span>{{rightSelection.length}}/{{rightTableData.length}}</span>
      </p>
      <div v-if="showQuery">
        <el-form :inline="true" :model="rightQueryCondition" class="query-form">
          <slot name="rightCondition" v-bind:scope="rightQueryCondition"></slot>
          <el-form-item>
            <el-button type="primary" @click="onRightQuerySubmit()">{{queryTexts[1]}}</el-button>
          </el-form-item>
        </el-form>
      </div>
      <el-table
        ref="rightTable"
        size="small"
        :max-height="maxHeight"
        :height="minHeight"
        :data="calcRightTableData"
        :row-key="tableRowKey"
        @row-click="handleRightRowClick"
        @selection-change="handleRightSelectionChange"
        border
        stripe>
        <el-table-column width="40px" type="selection"></el-table-column>
        <el-table-column
          v-for="col in rightColumns || leftColumns"
          :prop="col.id"
          :key="col.id"
          :label="col.label"
          :width="col.width">
          <template slot-scope="scope">
            <slot v-bind:scope="{row: scope.row, col: col}">
              <span>{{scope.row[col.id]}}</span>
            </slot>
          </template>
        </el-table-column>
      </el-table>
      <el-pagination
        v-if="showPagination"
        :total="rightTableData.length"
        layout="total">
      </el-pagination>
    </div>
  </div>
</template>

<script>
export default {
  name: 'EltTransfer',
  props: {
    value: {
      type: Array,
      default () {
        return []
      }
    },
    // 显示条件查询
    showQuery: {
      type: Boolean,
      default: false
    },
    // 显示分页
    showPagination: {
      type: Boolean,
      default: false
    },
    // 左侧分页回调
    paginationCallBack: {
      type: Function,
      default: function () {
        return new Promise((resolve, reject) => {
          try {
            resolve({ total: 0, data: null })
          } catch {
            return false
            // reject()
          }
        })
      }
    },
    // 标题文本
    titleTexts: {
      type: Array,
      default () {
        return ['待选项', '已选项']
      }
    },
    // 按钮文本
    buttonTexts: {
      type: Array,
      default () {
        return []
      }
    },
    // 查询按钮文本
    queryTexts: {
      type: Array,
      default () {
        return ['查询', '筛选']
      }
    },
    // 左侧参数
    leftColumns: {
      type: Array,
      default () {
        return []
      }
    },
    // 右侧参数
    rightColumns: {
      type: Array,
      default () {
        return undefined
      }
    },
    // 表格最小高度
    minHeight: {
      type: String,
      default: '300px'
    },
    // 表格最大高度
    maxHeight: {
      type: String,
      default: '500px'
    },
    // 表格行数据的Key
    tableRowKey: {
      type: Function,
      default (row) {
        return row && row && row.id
      }
    }
  },
  data () {
    return {
      leftTableData: [],
      rightTableData: this.value || [],
      pageIndex: 1,
      pageSize: 20,
      totalSize: 0,
      leftSelection: [],
      rightSelection: [],
      leftQueryCondition: {},
      rightQueryCondition: {},
      rightConditionTemp: undefined
    }
  },
  created () {
    this.handlePaginationCallBack()
  },
  computed: {
    hasButtonTexts () {
      return this.buttonTexts.length === 2
    },
    buttonClasses () {
      return ['transfer-button', { 'is-with-texts': this.hasButtonTexts }]
    },
    disabledLeftButton () {
      return !this.leftSelection.some(leftRow => !this.rightTableData.some(rightRow => this.checkObjectIsEqual(leftRow, rightRow)))
    },
    calcRightTableData () {
      if (this.showQuery && this.rightConditionTemp) {
        const conditionKeys = Object.keys(this.rightConditionTemp)
        return this.rightTableData.filter(data => {
          return conditionKeys.some(key => {
            const rowCellData = data[key]
            const condVal = this.rightConditionTemp[key].trim()
            if (rowCellData) {
              return String(rowCellData).indexOf(condVal) > -1
            }
            return true
          })
        })
      }
      return this.rightTableData
    }
  },
  methods: {
    handleLeftSelectionChange (selection) {
      this.leftSelection = selection
    },
    handleRightSelectionChange (selection) {
      this.rightSelection = selection
    },
    handleLeftRowClick (row) {
      if (!this.rightTableData.some(rightRow => this.checkObjectIsEqual(rightRow, row))) {
        this.$refs.leftTable.toggleRowSelection(row)
      }
    },
    handleRightRowClick (row) {
      this.$refs.rightTable.toggleRowSelection(row)
    },
    handleSizeChange (val) {
      this.pageSize = val
      this.handlePaginationCallBack()
    },
    handleCurrentChange (val) {
      this.pageIndex = val
      this.handlePaginationCallBack()
    },
    handlePaginationCallBack () {
      if (this.showPagination && this.paginationCallBack) {
        const condition = {
          pageIndex: this.pageIndex,
          pageSize: this.pageSize,
          ...this.leftQueryCondition
        }
        this.paginationCallBack.call(null, condition).then(result => {
          if (result && Array.isArray(result.data)) {
            this.leftTableData = result.data
            this.totalSize = result.total
          }
          this.$nextTick(() => {
            this.leftTableData.forEach(leftRow => {
              const isHave = this.rightTableData.some(rightRow => this.checkObjectIsEqual(rightRow, leftRow))
              this.$refs.leftTable.toggleRowSelection(leftRow, isHave)
            })
          })
        })
      }
    },
    handleRowStyle ({ row }) {
      if (this.rightTableData.some(rightRow => this.checkObjectIsEqual(rightRow, row))) {
        return {
          color: 'blue'
        }
      }
      return {}
    },
    handleSelectable (row) {
      return !this.rightTableData.some(rightRow => this.checkObjectIsEqual(rightRow, row))
    },
    addToRight () {
      for (const item of this.leftSelection) {
        const isHave = this.rightTableData.some(rightRow => this.checkObjectIsEqual(rightRow, item))
        if (!isHave) {
          this.rightTableData.push(item)
        }
      }
      this.$emit('input', this.rightTableData)
    },
    addToLeft () {
      this.rightSelection.forEach(item => {
        const index = this.rightTableData.findIndex(rightRow => this.checkObjectIsEqual(rightRow, item))
        if (index !== -1) {
          this.rightTableData.splice(index, 1)
          const leftRow = this.leftTableData.find(leftRow => this.checkObjectIsEqual(leftRow, item))
          if (leftRow) {
            this.$refs.leftTable.toggleRowSelection(leftRow, false)
          }
        }
      })
      this.$emit('input', this.rightTableData)
    },
    onLeftQuerySubmit () {
      this.handlePaginationCallBack()
    },
    onRightQuerySubmit () {
      this.rightConditionTemp = JSON.parse(JSON.stringify(this.rightQueryCondition))
    },
    checkObjectIsEqual (rowObj1, rowObj2) {
      return this.tableRowKey(rowObj1) === this.tableRowKey(rowObj2)
    },
    clear () {
      this.rightTableData = []
      this.$refs.leftTable.clearSelection()
      for (const key in this.leftQueryCondition) {
        this.leftQueryCondition[key] = undefined
      }
      for (const key in this.rightQueryCondition) {
        this.rightQueryCondition[key] = undefined
      }
      this.pageIndex = 1
      this.handlePaginationCallBack()
    }
  }
}
</script>

<style scoped>
  .transfer {
    font-size: 14px;
    display: flex;
    justify-content: center;
    align-items: center;
  }
  .el-icon-arrow-right, .el-icon-arrow-left {
    font-size: 40px;
    cursor: pointer;
  }
  .transfer-panel {
    border: 1px solid #EBEEF5;
    border-radius: 4px;
    overflow: hidden;
    background: #FFF;
    display: inline-block;
    width: calc((100% - 100px) / 2);
    max-height: 100%;
    box-sizing: border-box;
    position: relative
  }
  .transfer-panel .transfer-panel-header {
    height: 40px;
    line-height: 40px;
    background: #F5F7FA;
    margin: 0;
    padding-left: 15px;
    border-bottom: 1px solid #EBEEF5;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
    color: #000;
  }
  .transfer-panel-header span:last-child {
    position: absolute;
    right: 15px;
  }
  .transfer-buttons {
    display: inline-block;
    vertical-align: middle;
    width: 100px;
  }
  .transfer-button {
    display: block;
    margin: 0 auto;
    padding: 10px;
    border-radius: 4px;
    color: #FFF;
    background-color: #409EFF;
    font-size: 0
  }
  .transfer-button .button-text {
    margin-left: 2px;
    margin-right: 5px;
  }
  .transfer-button.is-with-texts {
    border-radius: 4px
  }
  .transfer-button.is-disabled, .transfer-button.is-disabled:hover {
    border: 1px solid #DCDFE6;
    background-color: #F5F7FA;
    color: #C0C4CC
  }
  .transfer-button:first-child {
    margin-bottom: 10px
  }
  .transfer-button:nth-child(2) {
    margin: 0 auto;
  }
  .transfer-button i, .transfer-button span {
    font-size: 14px
  }
  .query-form {
    margin: 5px;
  }
</style>

<style>
  .query-form .el-form-item {
    margin-bottom: 0;
  }
</style>
